[PATCH 05/14] iomap: Support THPs in invalidatepage

Matthew Wilcox (Oracle)
2020-10-14T09:20:19Z

If we're punching a hole in a THP, we need to remove the per-page
iomap data as the THP is about to be split and each page will need
its own. This means that writepage can now come across a page with
no iop allocated, so remove the assertion that there is already one,
and just create one (with the uptodate bits set) if there isn't one.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/iomap/buffered-io.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 95ac66731297..4633ebd03a3f 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -60,6 +60,8 @@ iomap_page_create(struct inode *inode, struct page *page)
iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
GFP_NOFS | __GFP_NOFAIL);
spin_lock_init(&iop->uptodate_lock);
+ if (PageUptodate(page))
+ bitmap_fill(iop->uptodate, nr_blocks);
attach_page_private(page, iop);
return iop;
}
@@ -494,10 +496,14 @@ iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
* If we are invalidating the entire page, clear the dirty state from it
* and release it to avoid unnecessary buildup of the LRU.
*/
- if (offset == 0 && len == PAGE_SIZE) {
+ if (offset == 0 && len == thp_size(page)) {
WARN_ON_ONCE(PageWriteback(page));
cancel_dirty_page(page);
iomap_page_release(page);
+ } else if (PageTransHuge(page)) {
+ /* Punching a hole in a THP requires releasing the iop */
+ WARN_ON_ONCE(!PageUptodate(page) && PageDirty(page));
+ iomap_page_release(page);
}
}
EXPORT_SYMBOL_GPL(iomap_invalidatepage);
@@ -1363,14 +1369,13 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
struct writeback_control *wbc, struct inode *inode,
struct page *page, u64 end_offset)
{
- struct iomap_page *iop = to_iomap_page(page);
+ struct iomap_page *iop = iomap_page_create(inode, page);
struct iomap_ioend *ioend, *next;
unsigned len = i_blocksize(inode);
u64 file_offset; /* file offset of page */
int error = 0, count = 0, i;
LIST_HEAD(submit_list);

- WARN_ON_ONCE(i_blocks_per_page(inode, page) > 1 && !iop);
WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) != 0);

/*
@@ -1415,7 +1420,6 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
*/
if (wpc->ops->discard_page)
wpc->ops->discard_page(page);
- ClearPageUptodate(page);
unlock_page(page);
goto done;
}
--
2.28.0